Method for molding resin member and injection molding apparatus

ABSTRACT

An injection molding apparatus used comprises a molten resin injector  15  for injecting a molten resin, and a die  12  connected to the molten resin injector and communicating with the molten resin injector so that the molten resin is injected into the die. A cavity having a prescribed shape is formed within the die in order to mold the injected molten resin into the prescribed shape. An opening of the die for guiding the molten resin to the outside is blocked so as to confine a molding object as an object for molding the resin member. A plate member  10  as a molding object is compressed onto the die  12,  and the molten resin is injected into the die while compressing the molding object. The molten resin is adhered on the molding object by being guided from the opening, and a solidified resin member comprising the solidified molten resin is bonded on the surface of the molding object. Consequently, the resin member having a prescribed shape is readily and promptly formed on the surface of the molding object.

TECHNICAL FIELD

The present invention relates to a method for molding a resin member andan injection molding apparatus.

BACKGROUND ART

When a resin member is fixed to a molding object such as a glass, theresin member is usually molded into a prescribed shape using a moldingapparatus followed by fixing the molded resin member onto the moldingobject using an adhesive or a clamping member. Fixing the resin memberis required, for example, when a vehicle component such as a vehicleglass as an wind shield glass is attached to the body of the vehicle.While the vehicle glass is usually bonded to the vehicle frame using anadhesive, the glass should be held to the body by some means beforeadhesive strength of the adhesive becomes sufficiently strong. In aconventional method for holding the glass, a special holding member(resin member) such as a clip is fixed to the glass, and the holdingmember is locked to the body. Accordingly, a molded holding member wasprepared before fixing the holding member to the glass in theconventional method, and the molded member is fused to the glass using aultrasonic welding machine.

The problem to be solved by the present invention is to provide a methodfor readily attaching a molded resin member on the surface of a moldingobject, and an injection molding apparatus to be used for this purpose.

DISCLOSURE OF THE INVENTION

The present invention for solving the problems above provides:

a method for molding a resin member using an injection molding apparatuscomprising:

a molten resin injector for injecting a molten resin; and

a die connected to the molten resin injector and communicating with themolten resin injector so that the molten resin is injected into the die,a cavity having a prescribed shape being formed within the die in orderto mold the injected molten resin into the prescribed shape,

wherein a molding object is compressed onto the die having an openingfor guiding the molten resin to the outside while blocking the openingso that the molding object as an object for molding the resin member isconfined therein, the compressed molten resin being adhered to themolding object so as to be guided from the opening by injecting themolten resin into the die, the resin member comprising the solidifiedmolten resin molded so as to be directly adhered on the surface of themolding object,

the molten resin being injected into the cavity while maintaining aninjection pressure of the molten resin of 350 kg/cm² or less.

According to the method above, the resin member having a prescribedshape can be readily and promptly formed on the surface of the moldingobject. Conventional methods comprise multisteps of once forming a resinmember by injection molding, applying an adhesive on the surface of amolding object, and bonding the resin member formed onto the moldingobject. However, these steps can be performed at once in the method ofthe present invention, enabling the time for molding the resin member tobe largely diminished.

The effect of forming the resin member as described above becomesevident when the method of the present invention is applied to vehicleglass members (for example a wind shield glass). For example, while afront glass is fixed to a vehicle frame with an adhesive in theconventional manufacturing process of vehicles, a clip as a holdingmember was attached to a glass member by bonding or clamping, and a partof the clip was inserted into holes formed in the vehicle frame.According to the method of the present invention described above,however, the clip is integrally formed with the glass member to enablethe clip to be formed on the glass member within a quite short period oftime while saving the number of steps such as a clip management step.The effect of the present invention is quite large since no inventorycontrol is required.

The present invention also provides an injection molding apparatuscomprising:

a molten resin injector for injecting a molten resin; and

a die having a cavity of a prescribed shape formed therein incommunication with the molten resin injector so as to inject the moltenresin within the cavity, the cavity comprising an opening for guidingthe molten resin to the outside from the cavity,

the die comprising the opening for guiding the molten resin to theoutside, a molding object being compressed onto the die while placing aresin member on the molding object as an object of molding by blockingthe opening, the molten resin guided from the opening being closelyadhered on the molding object by injecting the compressed molten resininto the die, and allowing a solidified resin member formed bysolidifying the molten resin to be bonded on the surface of the moldingobject. The present invention provides an apparatus for favorablyapplying the method of the present invention having the constitution asdescribed above.

The injection molding apparatus described above may be constituted so asto have an integrated main unit formed by providing an injection plungerfor injecting the molten resin from the molten resin injector by movingin a prescribed direction and an injection actuator for allowing theinjection plunger to move by being directly or indirectly coupled withthe injection plunger,

the injection molding apparatus further comprising, as a separate unitfrom the main unit, an injection driving source for feeding a firstmedium to the injection actuator by being coupled with the injectionactuator by means of a flexible first medium feeding member for feedinga driving medium (named as the first medium hereinafter) for energizingthe injection actuator, the main unit being able to move relative to theinjection driving source through the first medium feed member.

The main unit becomes lightweight by separately forming the main unitfrom the driving source for energizing the injection actuator. Forexample, the driving force required for a transfer device can be reducedwhen the main unit is used after transferring the main unit with thetransfer device, thereby enabling various transfer devices to beemployed to enable selection ranges of the transfer device to beexpanded while allowing running cost to be reduced.

Practically, an injection air cylinder may be employed as the injectionactuator, and an injection air feed device for feeding air to theinjection air cylinder may be provided as an injection driving source.Furthermore, the injection air cylinder may communicate with theinjection air feed device through an injection air duct as a firstmedium feed member in order to feed air by the injection air feeddevice. The main unit can be devised to be lightweight to an extentcapable of carrying by man power by providing the air cylinder at aportion responsible as a resin feed driving source, thereby making themachine to be quite functional as a manually operable tool.

The main unit may comprise a grasping member for allowing an operator tograsp the injection molding apparatus. The operator can delicatelyadjust the molding position and readily perform molding work of theresin member irrespective of working sites by providing such graspingmember.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view showing an example of the injection moldingapparatus of the present invention.

FIG. 2 is a side view of the partial cross section of the injectionmolding apparatus shown in FIG. 1.

FIGS. 3A to 3C schematically illustrate examples of the constitutions ofthe injection molding apparatus.

FIG. 4 is a cross section taken on line A—A in FIG. 2.

FIG. 5 is a cross section taken on line B—B in FIG. 2.

FIG. 6 is an enlarged view showing the main part of FIG. 1.

FIG. 7 is a process chart schematically describing the bonding processof the resin member.

FIG. 8A is a cross section showing an example of the shape of thecavity.

FIG. 8B is a cross section showing an example of the solidified resinmember molded in the cavity in FIG. 8A.

FIG. 8C is a cross section showing another example of the solidifiedresin member molded in the cavity in FIG. 8A.

FIG. 9A illustrates an example of bonding of the solidified resin memberto a vehicle glass.

FIG. 9B is a perspective view showing the enlarged main part in FIG. 9A.

FIG. 9C illustrates how the resin member functions as a temporaryholding stopper to the wind glass.

FIG. 10A is a cross section showing an example of modification 1 of thecavity shape illustrated together with a die.

FIG. 10B is a cross section showing the cavity shape after removing thedie from the cavity shown in FIG. 10A.

FIG. 11A is a cross section showing an example of a volume variablestructure before injecting a resin.

FIG. 11B is a cross section showing an example of a volume variablestructure after injecting the resin.

FIG. 12A is a cross section showing an example of modification 2 of thecavity shape illustrated together with a die.

FIG. 12B is a cross section showing the cavity shape after removing thedie from the cavity shown in FIG. 12A.

FIG. 12C is a perspective view showing an example for fitting a mountingmember into the resin member in FIG. 12B.

FIG. 13 is a view showing an example of entire construction using theresin member in FIG. 12.

FIG. 14A is a view showing an example of a die comprising a temperaturecontrol device.

FIG. 14B is a view showing another example of a die comprising atemperature control device.

FIG. 14C is a view showing a different example of a die comprising atemperature control device.

BEST MODE FOR CARRYING OUT THE INVENTION

The best mode for carrying out the present invention will be describedhereinafter with reference to the drawings. FIG. 1 shows a front viewconstituting a part of the injection molding apparatus of the presentinvention, and FIG. 2 shows a side view thereof. As shown in FIG. 1, theinjection molding apparatus 1 comprises a molten resin injector 15 forinjecting a molten resin, and a main unit 16 having a die 12 connectedto the molten resin injector 15 and formed so that the molten resin isinjected into the die. The die comprises a cavity with a prescribedshape therein so that the injected molten resin is molded into the shapeof the cavity. Injection of the resin as used in this invention includesan embodiment in which the injection pressure is large, as well as anembodiment in which the injection pressure is small, or so calledflow-through injection.

As shown in FIG. 1, the injection molding apparatus 1 comprises the die12 and molten resin injector 15 (named as an injector 15 hereinafter)integrated therewith. The die 12 comprises therein a cavity 14 (see FIG.6) communicating with the inside of the injector 15, and the moltenresin is injected so as to fill the cavity 14. Examples of the injector15 available include plunger type, pre-practice type and screw typeinjectors. The die 12 is fixed with a die fixing member 42 as shown inFIG. 2, and the die fixing member 42 and actuator fixing member (an aircylinder fixing member 44) for fixing the an injection air cylinder 32as an injection actuator are monolithically fixed with tie-bars 22.While a standard cylinder having a driving shaft as shown in thisembodiment may be used as the injection air cylinder 32 (and a clampingair cylinder 30 to be described hereinafter), air cylinders known in theart that can be conjectured by those skilled in the art such as aspecial cylinder (such as a rodless cylinder) may be also used.

The injector 15 comprises therein an injection plunger 34 coupled with adriving part (for example a driving shaft) of the injection air cylinder32, and the molten resin is injected into the die 12 with the injectionplunger 34 moving by being driven with the injection air cylinder 32.The die 12 is monolithically fixed with the injector 15 by means of thedie fixing member 42, air cylinder fixing member 44 and tie-bars 22,which comprises a part of the main unit 16.

As shown schematically in FIG. 3A, the main unit 16 comprises aninjection air feed device 60 (compressor, tank, after-cooler and thelike) as an injection driving source for feeding air as a first mediumto the injection air cylinder 32 (see FIG. 1). An injection air duct 52as a first medium feed member couples the injection air cylinder 32 andinjection air feed device 60 so that they are communicating with eachother. Various materials such as metals and non-metals (for exampleresins) may be used for the injection air duct 52, which are desirablyflexible. Particularly, operability by an operator is improved due tolightweight by using non-metallic materials (such as resins). However,the clamping actuator is not restricted thereto, and may be a motor,hydraulic cylinder and the like. For example, when the motor is employedas the actuator, an electric power supply source (electric source) maybe used as the injection driving source, and a conductive member (suchas a wire) may be used as the first medium feed member (the first mediumis electricity in this case). When the hydraulic cylinder is employed asthe injection actuator, a hydraulic pump may be used as the injectiondriving source (the first medium is an oil in this case).

The main unit 16 is movable relative to the injection driving source (orthe injection air feed device 60) through the injection air duct 52.Since the injection air feed device 60 is provided as a separate unitfrom the main unit 16, only the main unit 16 is movable withouttransferring the injection air feed device 60. In other words, theinjection air feed device 60 comprising the compressor, tank and aftercooler and having a considerable weight is not required to be moved.Accordingly, the main unit 16 can be manually transferred without usingany special transfer machine since the main unit itself is quitelightweight. A mechanical transfer device such as a robot having a smalldriving force is also available for the main unit 16, enabling selectionranges of the transfer device to be expanded. Furthermore, since aminute quantity of electrical energy is required for mechanicaltransfer, the transfer cost (for example the cost of electricity) may besaved.

As shown in FIG. 2, the main unit 16 comprises a hopper 50 as a startingmaterial feed part, which communicates with a material tank 41 providedat the molten resin injector 15 through a material feed passageway 40.The starting material is supplied by feeding a resin material into thehopper 50. While the starting material is supplied through the hopper 50in FIG. 2, supply of the material is not restricted thereto. Forexample, the material may be automatically or semi-automaticallysupplied with a resin material feed device 65 (see FIG. 3B) comprising aflexible hose of a material feed passageway 43 and independentlyprovided from the main unit 16 (for example, the resin material feeddevice 65 may be formed as a hopper, and the resin material isautomatically supplied by sensing shortage of the resin material; or thefeed port of the hopper may be opened and closed by operating a switchelectrically connected to the resin material feed device 65 that isprovided at the main unit 16 or provided independently from the mainunit 16). The hopper 50 may be omitted by independently providing theresin material feed device 65 from the main unit 16, enabling the mainunit 16 to be further lightweight. Otherwise, the main unit 16 becomesreadily movable by constructing the material feed passageway 43 with aflexible member (for example a hose member made of a resin).

The resin material supplied to the hopper 50 is stored in the materialtank 41, then transferred to a heating cylinder 39 as a plasticizingapparatus having a heater, and is converted into a molten resin by beingheated by the heating cylinder 39. As shown in FIG. 6, the resinmaterial converted into the molten resin is injected from a nozzle 23 tothe cavity 14 provided within the die 12 by the movement of theinjection plunger 34 after melting, and the cavity 14 is filled with themolten resin. The nozzle 23 is formed so that the opening area of thenozzle 23 is reduced at the injection side, and is constructed so thatthe injected resin is tapered, or so that the resin is injected so as tobe converged in one direction. The transfer speed and driving force ofthe injection cylinder 34 may be controlled by adjusting the pressure,flow rate and speed of air supplied to the injection air cylinder 32.For example, the condition of feed air may be controlled by an actuatorcontrol method known in the art by providing a pressure control valve,flow rate control valve and flow speed control valve at a part of theinjection air duct 52 in order to set the piston (rod) transfer speedand driving force of the injection air cylinder 32 at arbitrary values.

The material of such molten resin available is, for example,polypropylene (however, the resin is not restricted thereto, andexamples of the resin include synthetic resins known in the art mainlycomprising engineering plastics such as polyacetal, polyamide,polycarbonate, modified polyphenylene oxide, polybutylene terephthalate,polysulfone and polyphenylene sulfide, and other common plastics).

The injection pressure of the molten resin from the molten resininjector 15 to the cavity 14 is adjusted to a desired value. Too smallinjection pressure may cause insufficient filling of the molten resin.When the pressure is too large, on the other hand, the clamping forcefor preventing the resin from leaking from between the molding object(plate member 10) and die 12 should be increased, causing potentialdanger of damaging the molding object. Too large injection pressure mayalso cause leak of the molten resin from the gap between the die 12 andmolding object.

An opening is provided at the die 12 so as to be able to guide themolten resin to the outside of the cavity. The plate member 10 (forexample a glass member) that serves as the molding object is providedfor molding the resin by blocking the opening so that the plate memberserves as a part of the inner wall of the die 12. The plate member 10that serves as the molding object is compressed onto the die 12. Themolten resin is closely adhered on the molding object (plate member 10)while being guided from the opening by injecting the molten resin intothe die 12 while keeping the compressed state of the plate member,thereby bonding a solidified resin member formed by solidifying (forexample solidifying by cooling) the molten resin on the surface of themolding object. Consequently, the step for molding the solidified resinmember by injection molding, and the step for bonding the solidifiedresin member to the molding object are simultaneously performed,enabling the time required for molding the resin member to be largelyreduced. The material of the molding object is not restricted to theglass, and may be an organic substance such as a resin, wood, naturalleather, synthetic leather and paper, or a mixture of at least twosubstances selected therefrom. The molding object may be also aninorganic substance such as a metal or non-metal, and a mixture of themetal and non-metal. A mixture of an organic substance and inorganicsubstance may be also available. The method according to the presentinvention is particularly effective when the resin member is molded on afragile object such as a glass.

As shown in FIG. 8A, the cavity 14 formed in the die 12 comprises aperfectly filling part 14 a communicating the molten resin injector 15(See FIG. 1) for being perfectly filled with the molten resin, and animperfect filling permissible part 14 b communicating the perfectlyfilling part 14 a to allow the molten resin to permeate from theperfectly filling part 14 a while permitting the molten resin toimperfectly fill. As shown in FIG. 8B, the contact face (the contactface in a perfectly molded resin contact region 63) of the solidifiedresin member 6 with the molding object at a part (a perfectly moldedresin part 6 b) formed in the perfectly filling part 14 a maintains anarea required for bonding to the plate member 10 that serves as themolding object, and a sufficient bonding force is given to the contactface when at least the perfectly molded resin part 6 b is formed.Furthermore, the bonding force is reinforced by the contact face (thecontact face at an imperfectly molded resin contact area 61) with themolding object of the part (an imperfectly molded resin part 6 a) formedby the imperfect filling permissible part 14 b in the solidified resinmember 6.

The imperfect filling permissible part 14 b extends from the peripheryof the perfectly filling part 14 a to the outside thereof, and is formedso that the cross sectional area perpendicular to the extendingdirection (in other word, the direction of advance of the resin memberin the imperfect filling permissible part) decreases in accordance withthe distance from the periphery. The extending direction in FIG. 8A isparallel to the surface of the molding object (plate member 10). Theimperfect filling permissible part 14 b is outwardly extended from atleast a part of the periphery of the perfectly filling part 14 a so thatthe bonding area between molding object and molded resin memberincreases. The bonding strength is reinforced by increasing the bondingarea between the resin member and molding object by providing theimperfect filling permissible part. Actually, the cavity 14 is formed sothat the gap between the inner wall of the cavity 14 in the imperfectfilling permissible part 14 b and the surface of the molding object(plate member 10) is narrowed in accordance with the distance from theboundary between the imperfect filling permissible part 14 b andperfectly filling part 14 a as shown in FIG. 8A. The molten resin can behardly permeated into the portion remote from the nozzle 23 when themolten resin is injected into the cavity 14, and permeation of themolten resin becomes further difficult as the gap in the cavity 14 isnarrowed. The cavity 14 in FIG. 8A is constructed so that the distancefrom the tip of the nozzle is larger in the imperfect fillingpermissible part 14 b than in the perfectly filling part 14 a. In otherwords, since the molten resin invades the imperfect filling permissiblepart 14 b after filling the perfectly filling part 14 a, the injectionpressure required for filling the entire imperfect filling permissiblepart 14 b is larger than the injection pressure capable of filling theperfectly filling part 14 a. In addition, since the gap between theinner wall of the cavity 14 and plate member 10 is narrowed (or thecavity 14 is formed so that the cross section of the cavity (the crosssection of the molten resin passageway) is reduced in the direction ofadvance of the molten resin as the distance from the nozzle 23increases), a differential pressure is generated between the minimuminjection pressure (called as a required injection pressure for theperfectly filling part hereinafter) for enabling the perfectly fillingpart 14 a to be fully filled and the minimum injection pressure (calledas the minimum injection pressure for filling hereinafter) for perfectlyfilling the imperfect filling permissible part 14 b (in other words, thedifferential pressure between the minimum injection pressure when themolten resin starts to leak from the cavity 14 (called as a leakinitiating injection pressure hereinafter) and the injection pressurefor filling the perfectly filling part increases). Accordingly, theinjection pressure of the molten resin injector 15 may be determinedwith some margin.

FIG. 8B shows an example in which the resin is filled by invading intothe entire imperfect filling permissible part 14 b of the cavity 14, andFIG. 8C shows an example in which the resin invades in only a part ofthe imperfect filling permissible part 14 b, and does not arrive at thetip of the imperfect filling permissible part 14 b. The formercorresponds to injection of relatively a large quantity of the resin,while the latter corresponds to injection of relatively a small quantityof the resin. While the injection volume of the injector by one strokeis substantially constant in the injection mechanism employing a screwtype injector that injects the resin after metering with a screw, theinjection volume may be irregular in a plunger type injection mechanism(particularly when the size of the resin molding part is small).Therefore, the imperfect filling permissible part 14 b of the cavity 14may be considered to function as a kind of relief part that permitsirregular injection of the resin. The resin is perfectly filled up tothe imperfect filling permissible part 14 b by one stroke of injectionwhen the plunger mechanism is employed. When the injection volume is inexcess, the plunger stops at a latter half of the stroke of the plungersince the injection pressure (compression force of the plunger) isconstant, and the resin remaining in the cylinder without being injectedcan be used for the next injection. While a considerable bondingstrength is satisfied once the resin is bonded to the region 63 in FIG.8B as well as in FIG. 8C, more enhanced bonding strength may be expectedby permitting all or a part of the region 61 wider than the region 61 toserve as the resin bonding region.

While the molten resin is injected into the cavity while maintaining theinjection pressure of the molten resin low in the present invention, thelow pressure as used in the present invention means that pressure is lowas compared with the injection pressure (about 1,000 kg/cm²) in theconventional injection molding. For example, the resin is injected whileadjusting the injection pressure of the molten resin at 350 kg/cm² orless (desirably at 200 kg/cm² or less). This means that the pressure ofthe molten resin in the cavity is 250 kg/cm² or less, which is effectivewhen the molding object is a fragile substance such as a glass since thepressure applied on the molding object is also 250 kg/cm² or less. Apressure exceeding 350 kg/cm² may break the object when a fragilesubstance such as a glass is used as the molding object. The minimuminjection pressure may be close to 0 kg/cm², or 50 kg/cm² or more, solong as the molten is fluid.

The clamping mechanism will be described hereinafter.

The clamping mechanism comprises a compression member 18 for compressingthe plate member 10 by pushing out toward the die 12 side, and aclamping air cylinder 30 as a clamping actuator that is directly orindirectly coupled with the compression member 18 for allowing thecompression member 18 to relatively come close to and remote from thedie 12. As shown in FIG. 3C, the clamping air cylinder 30 is coupledwith a clamping air feed device 62 (a compressor, tank, after-cooler andthe like) as a clamping driving source for feeding air as a secondmedium through a clamping air duct 54 as a second medium feed member,and air is supplied from the clamping air feed device 62 through theclamping air duct 54. Various materials such as metals and non-metals(for example resins) may be used for the clamping air duct 54. Theclamping mechanism becomes lightweight by constructing it using anon-metal (for example a resin), and operability by the operator isimproved. The clamping actuator is not restricted to those describedabove, and a motor and a hydraulic cylinder may be used as in theinjection actuator. In this case, the second medium, or the secondmedium feed member exemplified in the injection actuator may be alsoused. Using an air cylinder as the clamping actuator may contribute theclamping mechanism to be lightweight and small size as in the case ofthe injection air cylinder 32 (FIG. 1). While a standard cylinder havinga driving shaft as exemplified as the clamping air cylinder 30 (FIG. 6)may be used as in the case of the injection air cylinder 32, anycylinders such as a special cylinder (for example a rodless cylinder)may be used so long as the cylinders are known in the art and readilyconjectured by those skilled in the art.

The clamping air feed device 62 (compressor, tank, after-cooler and thelike) may be provided as an independent unit from the main unit 16 as inthe injection air feed device, and the main unit 16 can be transferredwithout moving the clamping air feed device, thereby enabling the mainunit 16 as a main movable part of the injection molding apparatus 1 tobe lightweight while making the injection molding apparatus to be quitefunctional as a hand tool While the clamping air feed device 62 isindependently provided from the injection air feed device 60, they arenot always required to be different units. In other words, an air feeddevice may be simultaneously used for the injection and clamping aircylinders, and the air feed direction may be selected with a flow ratecontrol device (such as an electromagnetic valve).

The compression member 18 is coupled with the driving part (drivingshaft) of the clamping air cylinder 30, and comes close to or remotefrom the plate member 10 by being driven with the clamping air cylinder30. The plate member 10 is clamped in the direction of thickness by thedie 12 fixed relative to the main unit 16 and the compression member 18that pushes the plate member 10 toward the die 12 by being driven withthe clamping air cylinder 30 Consequently, the plate member is fixed tothe die 12. Such construction of the clamping mechanism permits theplate member 10 to be fixed to the die 12 with a given compression forceso that the surface of the plate member 10 serves as a part of the innerwall of the cavity 14.

The following synergetic effect may be expected by employing the glassmember as the molding object as described above, and by adjusting thecompression pressure. Since the glass member may be broken or suffer asever damage on the surface when the contact pressure between the glassmember (for example a vehicle glass member) and the die 12 (for example,applying several tons of the clamping pressure as in the conventionalinjection molding) is too large, it has been quite difficult to employ,or even to imagine, the glass member as a part of the die. However, thisis possible in the present invention by adjusting the shape of thecavity.

A buffer member 20 for reducing physical shocks when the molding objectis compressed by the compression member 18 is provided on at least apart of the contact face of the compression member 18 for compressingthe molding object. The buffer member may be made of an elastic member(for example a soft elastic member such as a rubber or an elastomer), ora cushioning material such as a resin or cloth (woven or non-wovenfabric) may be used. Providing the buffer member 20 permits shockscaused by compression of the compression member 18 onto the plate member10 may be relieved while effectively preventing the surface of the platemember 10 to be protected from being damaged by using a low hardnessmember (desirably a soft and elastic member such as a rubber, resin andcloth) as the buffer member.

As shown in FIG. 6, the plate member 10 as the molding object issupplied by being slid in a perpendicular or approximately perpendiculardirection relative to the direction for allowing the die 12 to comeclose to or remote from the compression member 18. The plate member 10may be supplied by a mechanical method (for example, using a robot forsupplying the plate member to a resin molding position while clampingthe plate member), or may be manually supplied. The plate member 10 ispositioned by making at least a part thereof to contact a positioningmember 38 located at the transfer side (for example, positioned byallowing its outer periphery to contact), and is fixed relative to thedie 12 by being compressed in the direction of thickness by beingclamped with the die 12 and compression member 18. An accuratepositioning is possible by positioning the plate member by allowing atleast a part thereof to contact while facilitating the positioning work.Particularly, the operator can definitely locate the positioning markwhen the plate member 10 is manually supplied.

The total length L₂ of the main unit 16 may be determined to be 50 cm orless as shown in FIG. 2. The main unit 16 may become large size andmanual transfer becomes difficult when the total length exceeds 50 cm,forcing the installation site and accommodation space to be widened.When the length is too small, on the other hand, the actuator becomesinevitably small that an effective injection pressure and clamping forcecannot be obtained. The weight of the main unit 16 may be determined inthe rage of 5 to 10 kg. Manual transfer becomes difficult when theweight exceeds 10 kg, while selection of a desirable actuator forrealizing desirable functions becomes difficult when the weight is lessthan 5 kg.

While the plate member 10 is clamped in the direction of thickness withthe die 12 and compression member 18 as described above, an inner wallis formed in the cavity 14 formed in the die 12 by being compressed bythe plate member 10 so that the solidified resin member 6 is molded bybeing protruded from the plate surface (for example, so as to protrudein an approximately perpendicular direction to the surface of theplate). The solidified resin member 6 is released from the die 12 byallowing the plate member 10 to depart from the die 12 in the verticaldirection after solidification (by allowing the plate member 10 to movein the vertical direction (downward in the drawing) as shown in FIG. 6or 7). Then, the solidified resin 6 spontaneously falls off from theinside of the cavity by the plate member's 10 own weight, when thecompression member 18 is allowed to move by the compression air cylinder30 (or when the compression member departs from the die 12) aftercompleting solidification of the solidified resin member 6. The methodfor allowing the plate member 10 to depart from the die 12 is notrestricted thereto, and the method also comprises holding the glassmember at a prescribed position by a holding device other than theinjection molding apparatus 1, and moving the injection moldingapparatus 1 itself in the vertical direction (for example, the operatorlifts up the injection molding apparatus by holding a grip member 13)after completing solidification of the solidified resin member.

While the plate member 10 is clamped with the die 12 and compressionmember 18 that come close to and remote from the plate surface in thevertical direction, an inner wall is formed so that the solidified resinmember 6 protrudes in the vertical direction (or in the approximatelyperpendicular direction) to the plate surface in the cavity 14 in thedie 12 compressed onto the plate member 10. The solidified resin isreleased from the die 12 by allowing the die 12 to depart from the platemember after solidification ((c) of FIG. 7). In other words, thesolidified resin member 6 may be pulled out of the inside of the cavity14 by allowing the die 12 to depart from the plate member 10 by allowingthe injection molding apparatus 1 to move, or by allowing the platemember 10 to depart from the die 12 (for example, the plate member 10falls down by allowing the compression member 18 to depart from the die12).

A sliding member 19 as a displacement member is provided as shown in (b)and (c) of FIG. 7 in the die. 12, wherein the displacement member isdisplaced between a protrusion position that protrudes toward the insideof the cavity from the inner face of the cavity 14 ((b) of FIG. 7) andan waiting position that is waiting without protruding from the innerface of the cavity ((c) of FIG. 7). The molten resin is injected intothe die 12 while the sliding member 19 remains to be protruded as shownin (b) of FIG. 7, thereby forming a depression 6 a corresponding to theprotrusion of the displacement member in the solidified resin member 6by allowing the molten resin to cool and solidify while the slidingmember 19 is protruding. The solidified resin member 6 is released outof the die 12 when the sliding member 19 is positioned at the waitingposition.

A solidified resin member having a depression may be formed withoutdividing the die by constructing the displacement member (actually thesliding member 19) so as to be able to displace in the die 12, therebypermitting the construction to be simple and the number of parts to bereduced. The depression 6 a serves, for example, as an engaging memberfor engaging the solidified resin member 6 with the frame of a vehicle,when the molding object is a vehicle glass to be described hereinafter(see FIG. 9A).

Since the engaging member may be monolithically formed by the method asdescribed above, no other components are needed for providing the engagemember, enabling the number of components to be reduced and inventorymanagement to be easy.

In an actual construction, a through hole 17 that penetrates the die 12from the outside to the inside of the cavity is formed, and the slidingmember 19 performs a reciprocating movement between the protrusionposition and waiting position in the through hole 17. An actuator thatis coupled with the sliding member 19, directly or indirectly throughanother member, may be provided for driving the sliding member 19, or itmay be manually operated by the operator.

A grip member 13 can be provided on the main unit 16 so that theoperator is able to grip the main unit 16. The relative position of theresin molding object to the main unit 16 can be adjusted by moving themain unit 16 while holding the grip member 13. While the grip member 13is held by the operator in this embodiment, the method is not restrictedthereto. The grip member may function as another coupling member that iscoupled with another main unit transfer device (for example, a robothaving a main unit fixing arm that is transferred to an arbitraryposition with a servo mechanism) for moving the main unit 16. Suchmechanism permits the main unit 16 to be transferred to an arbitraryposition with the robot, enabling automation of the machine.

The grip member 13 may have the following configuration. A handle 13 aas a grip position by the operator is provided as a rod member formedinto a rod, which is formed to be slender so that the axial directionthereof aligns parallel or approximately parallel to the longitudinaldirection of the main unit 16. The handle 13 a may be formed to beslender so that the axial direction thereof is parallel or approximatelyparallel to the contact direction between the die 12 and molding object.The contact direction and the longitudinal direction of the main unit 16are the same with each other in this embodiment. One end of the gripmember 13 is fixed to the main unit 16, and the grip member extends to adirection departing from the main unit 16 using the fixed position as abase point. In addition, the grip member is formed into a L-shape so asto be bent in a direction approximately parallel to the longitudinaldirection of the main unit 16. Forming the grip member into such shapepermits the grip member to be readily processed with a simple structurethat can be readily held by the operator. The operator is less fatiguedby gripping (or readily gripped) by forming the grip member as describedabove, when the operator holds the main unit 16 so that the longitudinaldirection of the main unit 16 comes to the vertical direction.

While the axial direction of the handle 13 a is approximately parallelto the longitudinal direction of the main unit 16 in this embodiment,the handle may be provided so that the axial direction of the handle 13a is perpendicular or approximately perpendicular to the longitudinaldirection of the main unit. Constructing the grip member so that theslender handle 13 a as a grip position is provided in the directionapproximately parallel or perpendicular to the longitudinal direction ofthe main unit 16 permit the main unit to be readily held by hand,thereby improving operability of the main unit 16 by the operator.

The shape of the grip member 13 is by no means restricted to the shapeas described above. Instead, various shapes are possible so long as theshapes are readily conjectured by those skilled in the art (for examplea cylindrical, ellipsoidal or rectangular handle, or shapes that roughlyfit the palm of the operator upon grasp by the operator). The attachmentposition of the grip member is also not particularly restricted (forexample, various positions such as in the vicinity of the air cylinder32 or injection cylinder 35).

A switch for switching injection of the resin may be provided at a partof the grip member 13. The switch is electrically connected to theinjection air cylinder and clamping air cylinder in order to startinjection of the resin by operating the switch. Alternatively, a switchelectrically connected to the air cylinder 30 may be provided at thegrip member 13 so that the die 12 is opened and closed, or clamped orreleased, by operating the switch. Such construction permits instructionsignals such as start of injection and die gripping to be given to themachine by a short stroke of a finger while the operator is holding thegrip member, thereby affording high operability of the machine.

An object having continuously changing flat part and curved part atleast at a part thereof may be used as the molding object, and thesolidified resin can be adhered on the surface of the flat or curvedpart. The term “continuous change” means that no steps and incisions areformed on the flat or curved part, and the surface is smooth.

An under coating material 70 may be applied for improving bondingability of the solidified resin member 6 to the molding object (platemember 10) in the region for bonding the solidified resin member 6 onthe molding object (plate member 10) prior to injection of the moltenresin. The under coating material may comprise toluene, or othersolvents and adhesives, which permit the solidified resin member to betightly adhered on the molding object.

A hanging member (for example a flexible material such as a flexiblemetallic wire rope and chain) for hanging the main unit 16 may beprovided in any of the main units described above. An eyebolt 80 (seeFIG. 1) may be provided for connecting the main unit 16 to the hangingmember. The operator can transfer the main unit 16 by holding the gripmember 13 while hanging the main unit 16 with a chain as the hangingmember. Consequently, the entire weight of the main unit 16 is notrequired to be supported by the operator (for example, the main unit ishung by the chain from the ceiling, and the operator is able to transferthe resin member molding apparatus 1 as if it is a pendulum), enablingworkability to be improved.

A winding device (for example a so-called ceiling crane or balancerhaving a winding reel for winding the wire rope or chain that enablesthe position of a hanging object to be freely changed at an arbitraryelevation) may be provided at a base point of the hanging member inorder to change the elevation of hanging of the main unit 16 inaccordance with the mode of use. The transfer range may be furtherexpanded by making the end of the chain (for example a joint to theceiling) as the hanging member to be movable (for example a guide railis provided at the ceiling, and the main unit is allowed to be movableby the guide rail).

The present invention may be applied to the vehicle glass as the platemember 10 formed into a plate shape as the molding object so that theresin member is adhered on at least a part in the vicinity of the outerperiphery of the vehicle glass. The following effects may be manifestedfor attaching the glass when the resin member is directly molded on thevehicle glass. For example, while the vehicle glass is usually bonded tothe frame of the vehicle body with an adhesive when the vehicle glasssuch as the wind shield glass is attached to the vehicle body in themanufacturing process of the vehicle, the glass should be held with somemeans before the adhesive has an enough bonding strength. Accordingly,the glass member is usually held using a special holding member such asa clip.

FIGS. 9A and 9B show examples for attaching the glass member (forexample a front glass) to the vehicle using the injection moldingapparatus 1. As described above, the solidified resin member 6 is formedon the surface of the vehicle glass (plate member 10) as describedabove, and the glass member is attached to the vehicle by inserting themolded solidified resin member 6 into attachment holes 101 previouslyformed on the frame of the vehicle 100 for positioning and temporaryholding (for example, the plate member 10 is mounted on the frame withthe adhesive between them while inserting respective resin members 6into the attachment holes 101). While the adhesive is previously appliedat the portions where the frame contacts the glass, the solidified resinmember 6 is locked into the attachment hole 101 formed on the frameuntil the bonding with the adhesive is secured. Specifically, thesolidified resin 6 is engaged with the frame using the depressions 6 i(see (b) and (c) of FIG. 7) formed on the solidified resin member 6 asengaging parts, and the vehicle glass is held on the frame.

Since the resin member 6 is previously integrated with the vehicle glass(plate member 10), a temporary holding resin member (or called as atemporary holding stopper) usually called as a clip is not required tobe managed as a separate component. Consequently, the inventorymanagement process may be reduced while reducing the number of thetemporary holding stoppers such as the clips. Moreover, two steps ofmolding the resin member as the temporary holding stopper and fixing theresin member can be arranged into one step, thereby largely contributingto reduction of the manufacturing time. While the vehicle glass wasexemplified as a vehicle component, the vehicle component is notrestricted thereto, and the molding object comprises various vehiclecomponents. When the molding object comprises the automobile wind glassas described above, and the resin member is used as a stopper fortemporarily holding the wind glass on the vehicle, the bases 93 (thebase 93 comprises the perfectly molded resin part 6 b (see FIGS. 8B and8C)) of the temporary holding stopper, which is formed with a distanceT₁ apart from the periphery of the wind glass WG (plate member 10) tothe inside as shown in FIG. 9C, can be formed by being extended alongthe longitudinal direction (the direction indicated by the arrows inFIG. 9C) of the base 93 by taking advantage of the imperfect fillingpermissible part. The molded part 6 c is formed using the imperfectfilling permissible part which is extended as described above as shownin FIG. 9C. Consequently, a urethane sealer 90 for hermetically sealingthe periphery of the wind glass by bonding to the vehicle body is notnarrowed, and appearance from the inside of the vehicle does not becomepoor. The seal width between the periphery of the wind glass andtemporary holding stopper is narrowed by forming a margin for moldingthe temporary holding stopper at the periphery of the wind glass towardthe inside to fail in maintaining hermetic sealing. However, theconstruction as described above can prevent such drawback. In addition,the margin formed for the temporary holding stopper at the inside of theperiphery of the wind glass can be seen from the inside of the vehicleto deteriorate the quality of the vehicle. However, the construction asshown in FIG. 9C can also prevent such drawback.

The following modification may be also employed in the presentinvention.

In FIGS. 10A and 10B, the imperfect filling permissible part is providedso that it is not adjoining to the molding object. The cavity shown inFIG. 10A is configured so that projections 6 j are formed on the outersurface of the solidified resin member 6 after molding as shown in FIG.10B, and the imperfect filling permissible parts 14 c are formed at thepositions where there is no problem for forming the projections 6 j.While the perfectly filling part 14 c is formed so as to communicate theimperfect filling permissible part 14 b in FIG. 10A, the position causesno problem by forming the projections 6 j, and the position is notrestricted so far as it is remote from the nozzle 23.

The die may have a variable volume structure by which the volume of thecavity increases in accordance with the pressure of the molten resin inthe cavity 14 as shown in FIGS. 11A and 11B. In FIG. 11A, the die 12 hasa communication passageway 14 d communicating with the cavity 14, and acore member 140 is provided to be slidable so as to block thecommunication hole 14 in the communication passageway 14 d. The coremember 140 is urged with an urging device such as a spring in thedirection toward the cavity 14. As shown in FIG. 11B, the core member140 is compressed by the molten resin having an increased pressure whenthe pressure of the molten resin is enhanced in the cavity 14, and movesin the direction to increase the volume of the cavity 14 against theurging pressure. A part of the communication passageway 14 d constitutesa part of the cavity 14 after the movement.

In FIG. 12A, the cavity 14 is configured so that the solidified resinmember 6 (FIG. 12B) after molding has a depression 6 f such as a grooveand hole, a molded part 6 g (the completely molded resin part 6 g)formed by the completely filled part 14 a constitutes the periphery ofthe depression 6 f, and the molded part 6 c (the imperfectly moldedresin part 6 c) by the imperfect filling permissible part 14 b is formedwithin the depression 6 f of the solidified resin member 6 (a brokenline 14 e indicates a boundary between the perfectly filling part 14 aand imperfect filling permissible part 14 b). This means that the upperface 6 d and side faces 6 e, 6 e of the solidified resin member 6 areperfectly molded, and the molded part 6 c by the imperfect fillingpermissible part is located within an area surrounded by an imaginaryplane 106 including the upper face 6 d and side faces 6 e, 6 e. Thisconfiguration is effective when the external shape should be defined asshown in FIG. 12C. While FIG. 12C shows when an attachment member 110 isattached to the solidified resin member 6, these solidified resin member6 and attachment member 110 are fitted with each other by forming agroove 110 a fitting into the external shape of the solidified resinmember 6 in the attachment member 110. Since the molded part 6 c by theimperfect filling permissible part 14 b does not affect for fitting solong as it is located within the depression 6 f, the shape of the moldedpart 6 c does not cause any problem. While FIGS. 12A to 12C show anexample having two nozzles for injecting the molten resin fromrespective nozzles 23, 23, the number of the nozzles is not restrictedthereto, and the die may be constructed to have single nozzle.

Alternatively, a back mirror 112 may be fixed to an attachment member110 that is fitted into the solidified resin member 6 by directlymolding the solidified resin member 6 onto the vehicle front glass(plate member 10) as shown in FIG. 13, using the method for attachingthe attachment member 110 to the solidified resin member 6 molded asshown in FIGS. 12A to 12C. In other words, the attachment member 110functions as a mirror base (mirror base for attaching the automobileroom mirror). The back mirror 112 can be readily attached to the frontglass by the method as described above without using the clamping memberand adhesive. The mirror base may be fitted into the external shape forattaching the room mirror, thereby avoiding the mirror from beingadversely affected for fitting so long as the molded portion using theimperfect filling permissible part is formed within the depression inthe solidified resin member. Of course, the clamping member and adhesivemay be used together for attachment. The mirror base (attachment member110) may be formed so that it is freely attachable to and detachablefrom the solidified resin member 6 (see FIG. 12C).

Otherwise, the temperature of the communication part 25 between themolten resin injector 15 (FIG. 1) and cavity 14 in the die 12 may becontrolled (for example in the range of 100 to 115° C.) with thetemperature control device provided around the communication part 25 forinjecting the molten resin into the die 12 as shown in FIGS. 14A to 14C.Such temperature control is quite effective for injecting the moltenresin at a low injection pressure (350 kg/cm² or less, desirably 200kg/cm² or less) as described above. Different from conventionalinjection molding using a high injection pressure, it is desirable tomaintain fluidity of the molten resin since the molten resin tends to beclogged at near the nozzle at a low injection pressure. Accordingly,good communication state is secured in the vicinity of the nozzle bymaintaining fluidity by controlling the molten resin at a prescribedtemperature (the temperature that does not affect fluidity of theresin), thereby permitting the injection rate and injection pressure tobe controlled with high accuracy even at a low injection pressure whilepreventing drawbacks such as clogging of the nozzle from occurring.

FIG. 14A shows an example in which a heating device 130 such as anelectric heater is provided around the communication part 25, whereinthe temperature in the vicinity of the communication part 25 is adjustedin the range of 100 to 115° C. using the heating device 130. A coolingpipe 134 for allowing a coolant (such as water) to flow is provided atthe die 12, and the cooling pipe 134 and coolant functions as a coolingdevice. The temperature in the vicinity of the communication part 25 isadjusted at the temperature described above using the heating device andcooling device. Although detailed descriptions of the temperaturecontrol of a given portion using the heater are omitted since the methodis well known in the art, various control methods (PID control, on-offcontrol and fuzzy control) may be employed.

A heat insulating device 132 (for example a heat insulating member suchas glass wool, air layer and the like) is provided around thecommunication part 25 as shown in FIG. 14B, and the temperature issuppressed from being decreased by increasing heat accumulation in thevicinity of the communication part 25 by means of the heat insulatingdevice 132. Since a heat is given in the vicinity of the communicationpart 25 by the molten resin's own heat, the cooling effect of thecommunication part 25 is effectively suppressed. Fluidity of the moltenresin is maintained without decreasing to hardly cause troubles offlowing. The heating device 130 and heat insulation device 132 may beused together as shown in FIG. 14C. While the cooling device is used inFIGS. 14A to 14C, the structure may comprise no such cooling device.

1. An injection molding apparatus comprising: a molten resin injectorfor injecting a molten resin; and a die in communication with saidmolten resin injector, so as to enable injection of molten resin intothe die, the die comprising: (a) a cavity having a prescribed shapeformed in said die, said cavity comprising: (i) a perfectly filling partin communication with said molten resin injector, so as enable theperfectly filling part to be perfectly filled with the molten resin, and(ii) an imperfect filling permissible part in communication with theperfectly filling part, so as to permit molten resin to flow from theperfectly filling part into the imperfect filling permissible part andimperfectly fill the imperfect filling permissible part, and (b) anopening in communication with said cavity, wherein, during injectionmolding using the injection molding apparatus, a molding object iscompressed onto said die at a molding object bonding surface, adjacentthe opening of the cavity, so as to block the opening of the cavity anddefine a surface of a solidified resin member formed during injectionmolding, said molten resin being closely adhered to said molding objectby injecting said compressed molten resin into said die, and allowing asolidified resin member to be formed by allowing said molten resin tosolidify and adhere to the bonding surface of said molding object. 2.The injection molding apparatus according to claim 1, furthercomprising: (a) an integrated main unit in communication with the moltenresin injector, said integrated main unit comprising: (i) an injectionplunger for injecting said molten resin from said molten resin injectorinto the perfectly filling part of the cavity of the die by moving theinjection plunger in a prescribed direction, and (ii) an injectionactuator for allowing the injection plunger to move by being directly orindirectly coupled with the injection plunger, (b) an injection drivingsource, separate from the integrated main unit, for feeding an injectiondriving medium to said injection actuator by being coupled with saidinjection actuator by means of a flexible first feeding member forfeeding the injection driving medium for energizing said injectionactuator, and said integrated main unit being able to move relative tosaid injection driving source through said flexible first feedingmember.
 3. The injection molding apparatus according to claim 2, whereinsaid injection actuator comprises an injection air cylinder, and saidinjection driving source comprises injection air feed means for feedingair to said injection air cylinder, said injection air cylinder incommunication with the injection air feed means through an injection airduct as said first medium feed member for feeding air by the injectionair feed means.
 4. The injection molding apparatus according to claim 2,wherein said molding object comprises a plate member formed into aplate, and wherein said integrated main unit further comprises aclamping mechanism for compressing the plate member onto said die, theclamping mechanism comprising a compression member for compressing andholding said plate member, said clamping mechanism being disposed suchthat the clamping mechanism is able to move relatively close to andapart from said die while clamping said plate member toward thedirection of thickness of the plate with the compression member and saiddie in order to secure said plate member at a position relative to saiddie.
 5. The injection molding apparatus according to claim 4, whereinsaid clamping mechanism further comprises: a clamping actuator directlyor indirectly coupled with the compression member for enabling saidcompression member to move relatively close to or apart from said die;and a clamping driving source for feeding a clamping driving medium tothe clamping actuator by being coupled to said clamping actuator bymeans of a flexible second feeding member for feeding the clampingdriving medium for energizing said clamp actuator, said integrated mainunit comprising said clamping actuator so as to be able to move relativeto said clamping actuator through said second feeding member.
 6. Theinjection molding apparatus according to claim 5, wherein said clampingactuator comprises a clamping air cylinder, and said clamping drivingsource comprises a clamping air feed means for feeding air to saidclamping air cylinder, said clamping air cylinder in communication withsaid clamping air feed means by means of a clamping air duct as saidsecond medium feed member in order to feed air by the clamping air feedmeans.
 7. The injection molding apparatus according to claim 4, forreleasing said solidified resin member adhered to the plate member fromsaid cavity by allowing said plate member to fall down by its own weightas a result of relieving the plate member from clamping by allowing saidcompression member to leave from said die.
 8. The injection moldingapparatus according to claim 2, wherein said integrated main unitfurther comprises: a grip member for allowing an operator to grasp theinjection molding apparatus.
 9. The injection molding apparatusaccording to claim 8, wherein the grip member is a slender L-shaped rodmember having a first end, as a base point, affixed to the integratedmain unit, and is bent such that an axial direction thereof alignsparallel to a longitudinal direction of said integrated main unit. 10.The injection molding apparatus according to claim 8, furthercomprising: a connecting member provided for connecting said integratedmain unit to a hanging member, wherein the operator can transfer themain unit by holding said grip member while hanging the main unit withthe hanging member.